COLUMBUS, Ohio (AP) — State agriculture officials are trying to keep a deadly walnut-tree disease from spreading from a southwestern Ohio county.

Officials say Butler County, north of Cincinnati, will be subject to a first-ever quarantine to keep thousand cankers disease from spreading. The quarantine, which goes into effect on Thursday, prohibits moving live walnut trees, lumber and wood out of the county.

The Ohio Department of Agriculture first confirmed the presence of thousand cankers disease in Butler County walnut trees in August. That came after the discovery of the insects known to carry the fungus, walnut twig beetles, in late 2012 and again in June.

State forestry officials estimate the value of black walnut at about $1.2 billion. That ranks the state No.?3 in the nation for overall black walnut inventory.